Nonstaining photographic developers



3,161,514 NUNSTAENHNG PHOTOGRAPHiC DEVELOPERS Richard W. Henri, Rochester, N.Y., assiguor to Eastman Kodak Company, Rochester, Nil, a corporation of New Jersey No Drawing. Filed Feb. 27, 196i, Ser. No. 91,622

Y 7 Claims. (Ci. 9d--d6) developers which exert considerable solvent action for the silver halide. The formation of the stain is believed to be due to the deposition of dissolved silver halide around nucleating centers present in the emulsion. The stain is usually metallic by reflected light, and yellow or brown by transmitted light, and may have considerable printing density.

The silver stain or scum, usually referred to herein simply as stain, is more likely to be produced in used photographic developers than in fresh photographic developers and becomes increasingly pronounced with extended developing times. Further, aged silver halide negative photographic films have a greater tendency to produce silver stain than the corresponding fresh silver halide negative photographic films.

It is an object of this invention to prevent the formation of silver stain when silver halide negative emulsions are developed. A further object is to provide photographic developers containing an agent which prevents or greatly reduces silver stain. Another object is to provide tine grain photographic developers of improved properties. A further object is to provide a process for developing silverhalide negative emulsions, under conditions having considerable solvent action for silver halide, in the presence of an agent which effectively inhibits staining.

I have discovered that chlororesorcinol (1,3-dihydroxy- 4-chlorobenzene) elfectively inhibits the formation of silver stain which is frequently produced when high speed silver halide negative emulsions are developed under conditions having considerable solvent action for the silver halide. Thus, chlororesorcinol inhibits or prevents the formation of silver stain which is ordinarily produced when high speed silver halide negative emulsions are de veloped in fine grain photographic developers which exert considerable solvent action for the silver halide. The chlororesorcinol is normally added to the developer. However, it may be incorporated in the photographic emulsion. As the developer becomes exhausted it can be renewed by addition of developer-replenisher containing a suitable amount of chlororesorcinol.

The amount of chlororesorcinol used varies from about 0.05 to about 10.0 grams per liter of developing solution. The preferred range is from about 0.1 to about 5.0 grams per liter of developing solution. The addition of even the lowest concentration of the chlororeso-rcinol greatly reduces the intensity of the stain. Higher concentrations frequently entirely prevent staining.

The use of resorcinol in a photographic developer is known. While tests made by me disclose that resorcinol shows antistain action chlororesorcinol is a much more powerful ant-istain agent. Similarly, the use of chlorohydroquinone (2 chloro 1,4-dihydroxybenzene) in a photographic developer is known. I have found that the antistaining action of chlorohydroquinone is weak relative to that of chlororesorcinol, and is approximately United States Patent 3,151,514 Patented ec. 15, 1964 der ordinary conditions of use. The outstanding antistaining action of chlororesorcinol could not have bee predicted from the prior art.

illustrative of the silver halide negative emulsions that can be advantageously developed in the presence of chlororesorcinol are the emulsions present in Kodak Panatomic-X, Kodak Verichrome Pan, Kodak Plus-X Pan, Kodak Tri-X Pan, Kodak Royal-X Pan, Ansco All- Weather Pan, Ansco Super Hypan, Ansco Superpan Press, Gevaert X-L Pan, Ilford HP3, ilford HPS and Ilford FF-3 photographic film. All of these photographic films have negative speed silver bromoiodide emulsions. They are merely illustrative and not limitative of the photo graphic films that can be developed with advantage in the presence of chlororesorcinol.

The photographic films mentioned hereinbefore and other brands of photographic film corresponding thereto have high speed silver halide negative emulsions even though they vary greatly in their speed ratings.

The use of chlororesorcinol as an ant-istaining agent is not restricted to any particular photographic developer or class of photographic developers. So far as I am aware it can be used with any of the known photographic developers. The photographic developer solution can have the agents usually present therein, e.g. photographic developer, a preservative such as sodium sulfite and an alkaline agent such as sodium hydroxide or sodium cars bonate. Other ingredients such as potassium bromide, for example, can also be present. Hydroquinone, paramethylaminophenol' sulfate,- paraphenylenediamine, paminophenol, 1 phenyl-3-pyrazolidone, 4,4-dirnethyl-lphenyl 3-pyrazolidone, l-phenyl-4-ethyl-3-pyrazolidone, 2,4-diaminophenol and pyrogallol are illustrative of the developing agents that can be employed. Mixtures of developing agents such as hydroquinone and paramethylaminophenol sulfate, and 4,4 dimethyl-l-phenyl-3-pyrazolidone and hydroquinone, for example, can be employed.

Sodium thiocyanate, potassium thiocyanate, ammonium thiocyanate, sodium chloride, ammonium chloride, ethylenediamine, 1,3,5-triaminobenzene, ethanolam-ine, diethanolamine, sodium thiosulfate and sodium sulfite are illustrative of the silver halide solvents that can be present during the development step.

The following examples illustrate my invention.

EXAMPLE 1 tration of the chlororesorcinol increased. The higher concentrations of chlororesorcinol (from about 0.2 gram upward) entirely prevented staining.

' EXAMPLE 2 A solution of Kodak Developer D-25 containing 0.5 gram of chlororesorcinol per liter of developer solution was exhausted with Kodak Verichrome Fan Film and replenished with Kodak Replenisher DK-ZSR containing 1.0 gram of chlororesorcinol per liter. The replenisher was added at the rate of 1 oz. per -square inch roll of film. Exhaustion of the developer was carried out to the equivalent of one hundred 80-square inch rolls of film per gallon. A total of 100 ounces of replenisher was added to the starting developer solution after it had been exhausted as described above. Even the exhausted developer was found to have very low scumming or staining propensity. The replenished developer had very little or no scumming or staining propensity. By contrast the unmodified Kodak Developer D-25 used as a control produced extremely dense scum or stain under the severe conditions of this test. The scumming or staining pro pensity of the unmodified D-25 developer increased as the test proceeded.

Kodak Developer D-25 and Kodak Replenisher DK 25R, and their use, are described in the Kodak Data Book, 5th edition (first 1960 printing), entitled Processing Chemicals and Formulas for Black-and-White Photography.

EXAMPLE 3 Kodak DK-ZO developer was modified by the addition of (a) resorcinol, and (b) chlororesorcinol at concentrations of 0.5 and 1.0 gram per liter. A sample of aged Kodak Royal Pan Film which showed severe staining propensity in the unmodified developer was processed in these solutions for minutes at 80 F. The following stain densities were obtained:

Example 3 was repeated in part using a fresher sample of Kodak Royal Pan Film. A stain density of 0.03 was obtained using developer No. 1 whereas no stain was obtained using developer No. 2.

EXAMPLE 5 Example 3 was repeated in part using a sample of Kodak Royal Fan Film having a greater staining propensity than the film used in Example 4 but less than that in Example 3. A stain density of 0.08 was obtained using developer No. 1 whereas no stain was obtained using developer No. 2.

Other photographic developers that can be modified with chlororesorcinol include Kodak Developer D23, Kodak Developed D-76, Kodak Developer SD21 and Kodak Developer SD-28, for example. These developers are merely illustrative and not limitative of the developers that can be modified with chlororesorciuol.

The compositions of Kodak Developer DK-20, Kodak Replenisher DK-25R, Kodak Developer SD21 and Kodak Developer SD-28 are given hereinafter.

Kodak Developer DK-20 Na SO (desiccated) 100.0 Sodium metaborate 20.0 H O to make 1 liter.

Kodak Developer SD-21 Elon 2.0 Hydroquinone 5.0 Na SO (desiccated) 100.0 Borax 8.0 Boric acid 8.0 KBr 0.25 H O to make 1 liter.

Kodak Developer SD-28 Elon 1.5 Hydroquinone 1.3 Na SO (desiccated) 75.0 Borax 4.5 KBr 0.4

H 0 to make 1 liter.

The compositions of D-25, D-23, and D-76 are as follows:

Kodak Developer D-25 Water to make 1.0 liter.

Dissolve chemicals in the order given.

I have also discovered that m-cresol, ortho phenylphenol, pentachlorophenol, and thiobenzanilide possess antistaining activity. However, while these compounds are useful antistaining agents they do not possess the outstanding antistaining activity that chlororesorcinol has.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

I claim:

1. A photographic developing solution containing (a) a silver halide photographic developer selected from the group consisting of hydroquinone, paramethylaminophenol sulfate, paraphenylenediamine, p-aminophenyl, 2,4-diaminophenol, pyrogallol and a 1-phenyl-3-pyrazolidone;

(b) an alkaline material;

(c) a silver halide solvent in an amount that is has a minimum solvent action equal to about 75 grams per liter of sodium sulfite; and

(d) from about 0.05 to about 10.0 grams of chlororesorcinol per liter of the developing solution.

2. A photographic developing solution according to claim 1 containing from about 0.1 to about 5.0 grams of chlororesorcinol per liter of the developing solution.

3. A photographic developer solution Containing as its essential ingredients for one liter of developer solution:

Grams Paramethylaminophenol sulfate 7.5 Sodium sulfite, desiccated 100.0 Sodium bisulfite 15.0 Chlororesorcinol 0.05 to 10.0

4. A photographic developer solution containing as its essential ingredients for one liter of developer solution:

Grams Paramethylaminophenol sulfate 7.5 Sodium sulfite, desiccated 100.0 Sodium bisulfite 15.0 Chlororesorcinol 0.1 to 5.0

6. In the process for developing an exposed high speed silver halide negative emulsion with a silver halide photographic developer solution containing a silver halide photographic developer selected from the group consisting of hydroquinone, paramethylaminophenol sulfate, paraphenylenediamine, p-aminophenol, 2,4-diaminophenol, pyrogallol and a l-phenyl-3-pyrazolidone, an alkaline material and a silver halide solvent in an amount that it has a minimum solvent action equal to about grams per liter of sodium sulfite, the improvement which consists in carrying out the developing reaction in the presence of from about 0.1 to about 5.0 grams of chlororesorcinol per liter of the developing solution.

7. In the process for developing an exposed high speed silver halide negative emulsion with a paramethylaminophenol sulfate photographic developer which exerts considerable solvent action for the silver halide the improvement which consists in carrying out the developing reaction in the presence of from about 0.1 to about 5.0 grams of chlororesorcinol per liter of the developing solution.

References Cited in the file of this patent Henn: PSA Journal, 19B, 1953, pp. 1468. 

1. A PHOTOGRAPHIC DEVELOPING SOLUTION CONTAINING (A) A SILVER HALIDE PHOTOGRAPHIC DEVELOPER SELECTED FROM THE GROUP CONSISTING OF HYDROQUINONE, PARAMETHYLAMINOPHENOL SULFATE, PARAPHENYLENEDIAMINE, P-AMINOPHENYL, 2,4-DIAMINOPHENOL, PYROGALLOL AND A 1-PHENYL-3-PYRAZOLIDONE; (B) AN ALKALINE MATERIAL; (C) A SILVER HALIDE SOLVENT IN AN AMOUTN THAT IS HAS A MINIMUM SOLVENT ACTION EQUAL TO ABOUT 75 GRAMS PER LITER OF SODIUM SULFITE; AND (D) FROM ABOUT 0.05 TO ABOUT 10.0 GRAMS OF CHLORORESORCINOL PER LITER OF THE DEVELOPING SOLUTION. 